The instant invention relates to a device for automatic opening and mixing of fiber bales by means of a bale opening device which is suspended over the bales from the bridge of a machine frame made in the form of a portal and capable of travelling along a guide rail and of being lowered upon said bales, said bale opening device being futhermore equipped with a conveying device.
When fiber bales are opened automatically and the fibers are mixed, the possiblity must exist to open as great a number as possible of fiber bales. At the same time it should be possible to lay down the bales as easily as possible within the most limited amount of space without havnig to place the bales on special tables or similar supporting means. Furthermore, it should be possible to install the bale opening device in any plant area set aside for this purpose without much floor space being used. Devices for the automatic opening and mixing of fiber bales having a tower-like machine frame on which the bale opening device is attached on one side in the form of a boom are known in published German Patent application number 3,208,346. The entire travelling and lifting mechanisms, including the conveying device for the removal of the opened fiber material are installed in this machine frame. For reasons of stability alone, this machine frame occupies much space in relation to the working width of the bale opening device, space which is lost to the placement of bales. To utilize this lost space fully, it is usually used for the pneumatic or mechanical conveyors which remove the opened fiber material. Such a conveyor belt or conveyor channel makes it impossible to reach from that side, the area on which the bales are laid upon.
Another device is known in U.S. Pat. No. 4,000,541, in which the machine frame consists of a bridge supported on both sides, from which the actual bale opening device is suspended.
Here too, the conveying and driving means, as well as a weighing device, are contained in one of the machine frame sides which support the bridge. The fiber material is conveyed in a perpendicular direction to the sense of travel of the machine frame to this weighing device, in which a fiber mixing process is effected according to weight, and from which the material, mixed by weight, is dropped on a conveyor belt running alongside the path of travel of the machine frame. All of these devices have in common that they are extraordinarily costly and also reduce accessibility and hinder the positioning of the bales to a great extent. The space requirements are very great in relation to the working width.
The object of the instant invention is to create a device for the automatic opening and mixing of fiber bales which is simple in its construction and utilizes the available space to the fullest extent while avoiding the above-mentioned disadvantages.
This object is achieved according to the invention in that the bale opening device is a plucker roll, the rotational axis of which is perpendicular to the direction of movement of the machine frame and the working width of which comes to at least 75% of the overall width of the machine frame.
In a further embodiment of the device according to the invention a bridge is provided which connects the two sidewalls to each other, said sidewalls being equipped with runners and being at a distance equal to at least two bale widths from each other. Due to the fact that the sidewalls hold, between them, five fiber bales laying side-by-side with their long sides touching, the mixing of the fibers is further improved and intensified. In a space-saving embodiment the thickness of the sidewalls is 30%, preferably 20% of the working width of the plucker roll since they are essentially used only as supports and as an undercarriage. All the devices taking up space are located in the bridge and in the area of the bridge.
The plucker of bale opening roll of the invention is advantageously supported on a side capable of being lifted and lowered. The movement of the slide in a vertical direction is made possible by the fact that the slide is suspended at its two ends from chain-like drive transmitting elements which are laid over a common drive shaft. The movement of the slide in a defined plane is achieved by guiding the slide in straight guides in the sidewalls. The fact that runners of the machine frame are driven synchronously by chains or toothed belts ensures trouble-free travel capability of the device.
To prevent flying fibers and for reasons of safety, the drive-transmitting elements are installed in the sidewalls of the machine frame. To save space, the drive motors of the slide and the runners are installed in the bridge. Any torsion of the driven shafts is compensated by the fact that the drive motors transmit their drive force to the shafts near the center between the sidewalls.
A limitation of the quantity of fibers removed by the bale opening roll is achieved by installing holding-down rolls on the slide, parallel to the bale opening roll and in its proximity. The holding-down rolls are preferably driven at the travelling speed of the machine frame.
In a further, space-saving embodiment of the device, the drive motors used to rotate the bale plucker roll and the holding-down rolls are supported on the slide. Due to the fact that the bale plucker roll is equipped with a rake-like stripping element extending over its working width and located behind said bale plucker roll in relation to its direction of rotation, excess fiber quantities are stripped from the bale opening roll and are conveyed back to the bale surface.
Air pollution by flying fibers and dust is prevented by the fact that the area between the bridge and the slide is closed off by a cover extending over the working width of the bale plucker roll. The cover consists of at least one covering metal sheet which is guided in the sidewalls and can be moved up and down by the slide in the manner of a window blind. However, two cover metal sheets overlapping each other and fitting space-savingly into the bridge when the side is in its uppermost position are preferably used as the cover.
In a preferred, even more space-saving further embodiment of the device according to the invention, a suction channel is provided in a fixed position above the bales and is the conveying device for the fiber material taken from the bales. Good access from all sides is thereby provided to the surface on which the bales are laid down.
Uniform removal, by suction of the fiber material taken from the bales, over the entire working width of the bale opening roll, is achieved through the fact that the suction channel is connected by conduits to two suction openings in a suction hood covering the bale plucker roll. The removal by suction of the fiber material, also in the outermost end zones, is ensured through the fact that the suction openings are located near the ends of the bale plucker roll. In order to enable the conduits to follow the vertical movement of the bale plucker roll and of the suction hood, they are made at least in part in the form of telescoping bellows. The connection between the conduits and the suction channel is preferably established so that the conduits end in movable connection openings lying across from each other which are part of a longitudinal slit in the suction channel, the slit being capable of being closed by a covering band. The movable connection openings are preferably located on a carriage coupled to the machine frame via fork-like carriers.
Secure closing of the longitudinal slit, even when negative pressure is not present in the suction channel, is achieved through the fact that the covering band is held in closing position by magnetic force. The path of travel of the machine frame is preferably adjustable by means of a pulse counter installed on the suction channel. The impulse counter is thus protected from damage.